Algae are simple, single-celled plants that can inherently produce lipids and other materials that can be processed to create biofuels, plastics and other materials traditionally derived from petrochemicals. Algae produce these valuable materials using nothing more than sunlight, carbon dioxide, fresh or salt water, and trace amounts of nutrients. Further, production of biofuels from algae results in few unwanted waste products. Accordingly, algae are a major potential source of renewable energy and petrochemical replacement materials.
One problem with the use of algae as a renewable energy and materials source has been the extraction of lipids or other useful materials from the algae. Algae have a durable cell wall that must be disrupted in order to effectively obtain the useful materials inside the cell. Various methods have been tried, but all suffer from deficiencies. For example, sonication methods use sound waves to break open algal cells, but is expensive and inefficient. Mechanical pressure may be used to burst algal cells, but is also expensive and difficult to scale up for bulk processing. Electroporation uses high powered electric fields to break cells open, but is very energy intensive and costly. Enzymatic extraction uses enzymes to break down algal cell walls in a highly efficient manner, but is extremely expensive and results in contamination of the resulting biomass. Finally, centrifuge-based methods, including one method using small ceramic balls, may also be used to burst algal cell walls, but these techniques are unproven at a large scale and involve large equipment and uncertainties in process parameters, such as flow rates.
Accordingly, there is a need for other methods and systems for disrupting the algal cell walls while leaving the useful materials from the algae substantially in a useful form.